REGULATOR REGIONS OF G PROTEINS

Abstract: A molecule having a peptide sequence of 80 or fewer amino acid residues containing the amino acid sequence of an anticouplone of any of the G proteins, which molecule is useful for inhibiting activation of the G protein by its G-coupled receptor.

Description: REGULATOR REGIONS OF G PROTEINS The field of the invention is cell receptor-based signal transduction. Background of the Invention Guanine nucleotide-binding proteins (G proteins) are a family of signal transducers which are found associated with the plasma membrane within eukaryotic cells, and which act to relay signals from certain cell- surface receptor molecules (G-coupled receptors) to effectors in the plasma membrane. G proteins are functional dimers consisting of α (Gα) and βy (Gβy ) subunits (Stryer et al., Ann. Rev. Cell Biol. 2:391-419, 1986) . Some presently-known members of this family include the G proteins termed G ol , G o2 , G i;L , G i2 , G i3 , G s , G g , and the G -related family which presently includes G ii' G 12' G i3' G 14' G 15' anc - G i6 ( see / e -g-/ Kaziro, "Structures of the Genes Coding for the α Subunits of G Proteins", Chapter 11 in ADP-ribosylatinq Toxins and G Proteins (Moss, J. , and Vaughan, M. eds.) ppl89-206, American Society for Microbiology, Washington, D.C., 1988) . Each individual G protein is characterized as such by the particular α subunit species (e.g., G ol α, G o2 α, etc.) which forms the α portion of the dimeric protein. In their unstimulated condition, G proteins are α?γ forms bound to guanosine diphosphate (GDP) ; upon receptor stimulation they dissociate into GTP-bound Gα and nucleotide-free Gjøγ, leading to the activation of the next effector protein in the cascade. In at least one case, this activation results in the opening of a calcium channel in the membrane, thereby increasing calcium influx in the cell (Kojima et al., Biochem. Biophys. Res. Commun. 154:9-19, 1988; Matsunaga et al.. Am. J. Physiol. 255:C442-C446, 1988). Okamoto et al. (Cell 62:709-717, 1990; hereby incorporated by reference) identified the region of one G-coupled receptor protein (insulin-like growth factor II receptor, or IGF-IIR) which directly interacts with and activates G i2 ; this region of IGF-IIR is sometimes referred to as that receptor's "couplone". A synthetic peptide (termed "Peptide 14") having a sequence identical to that of IGF-IIR's couplone was found to bind to and activate G i2 . Studies on synthetic variants of this peptide permitted Okamoto et al. to posit a critical peptide length (10 to 17 residues) and a motif for the couplone: two B ' s at the amino terminus of the peptide, and B-B-X-B or B-B-X-X-B at the carboxy terminus, where B is a basic amino acid (Lys, Arg, or His) and X is any nonbasic amino acid. In another G-coupled receptor, β 2 - adrenergic receptor (/32AR) , a G s -activator region termed 3III-2 has been identified in the third intracellular loop of 32AR (Okamoto et al., 1991a) . Summary of the Invention Applicants have identified the precise region on each of the known eukaryotic G proteins which interacts directly with the associated G-coupled receptor proteins. This region, termed the "anticouplone" or regulator region of the G protein, has been found to be critical to the function of the G protein, and therefore to signal transduction by the associated receptor. The invention thus encompasses a molecule of 80 or fewer amino acid residues (preferably 50 or fewer, more preferably 40 or fewer, and most preferably 30 or fewer) containing the amino acid sequence of an anticouplone of any of the G proteins (e.g., a mammalian G protein such as G ol , G o2 , G ii' G i 2 ' G i 3 ' G q' and G s) > τhe anticouplone region of a given G protein is located near the carboxy terminus of the G protein, from the 4th residue from the carboxy terminus at least to the 18th residue from that terminus, inclusive, and preferably to approximately the 27th residue from that terminus, inclusive. The molecule may contain an amino acid sequence defined by DXXXXVIIKNNLXXC (SEQ ID NO: 1) , where X denotes any amino acid (up to two of which may be deleted) and the other letters represent specific amino acids according to the standard single-letter amino acid code. More preferably, the peptide sequence is defined by DAVTXVIIKNNLKXC (SEQ ID NO: 2) . Specific examples of such a sequence include DAVTDVIIKNNLKDC (SEQ ID NO: 3), DTKNVQFVFDAVTDVIIKNNLKDC (SEQ ID NO: 4), DAVTDVIIKNNLKEC (SEQ ID NO: 5) , and DTKNVQFVFDAVTDVIIKNNLKEC (SEQ ID NO: 6) . Another version of the molecule of the invention includes the sequence DAVTXIIIAXNLRXC (SEQ ID NO: 7); examples include DAVTDIIIANNLRGC (SEQ ID NO: 8) , NNIQWFDAVTDIIIANNLRGC (SEQ ID NO: 9) , DAVTDIIIAKNLRGC (SEQ ID NO: 10), or NNIQFVFDAVTDIIIAKNLRGC (SEQ ID NO: 11) . Other molecules of the invention include a sequence NDCRDIIQRMHLRQY (SEQ ID NO: 12), DTENIRRVFNDCRDIIQRMHLRQY (SEQ ID NO: 13), AAVKDTILQLNLKEY (SEQ ID NO: 14), or DTENIRFVFAAVKDTILQLNLKEY (SEQ ID NO: 15) . The molecules of the invention may be employed in a method of inhibiting activation of a given G protein by a G-coupled receptor on a cell, which method includes the step of contacting the cell with, or otherwise introducing into the cell, a molecule containing the anticouplone sequence of the G protein, which molecule contains 40 or fewer amino acid residues. This method may be carried out, for example, by local or systemic administration of the appropriate peptide or modified peptide, or by introducing into the cell a nucleic acid encoding the anticouplone peptide together with all promoters and other elements necessary for expression of the peptide from the nucleic acid. Techniques for constructing such a nucleic acid and introducing it into the target cells are well known to those of ordinary skill in the art. Where the G protein of interest is G L1 , G i2 , or G i 3 ' ttle targeted receptor may be, for example, insulin-like growth factor II receptor (IGF-IIR) , muscarinic acetylcholine receptor (mAChR) , somatostatin receptor, D 2 -dopamine receptor, α 2 -adrenergic receptor, adenosine receptor, thrombin receptor, TGF3 receptor, or any other receptor which is functionally coupled to one of those G proteins. Where the G protein of interest is G Ql or G o2 , the receptor may be, for example, γ-butyric acid (GABA) receptor, somatostatin receptor, muscarinic acetylcholine receptor (mAChR) , α 2 -adrenergic receptor, adenosine receptor, thrombin receptor, or TGF/3 receptor. Examples of G s -linked receptors include ;0 2 -adrenergic receptor, glucagon receptor, IL-1 receptor, and O ± - dopamine receptor; while examples of G -linked receptors include the PTH/PTHrP receptor, calcitonin receptor, endothelin receptor, T cell receptor, angiotensin receptor, platelet activating factor receptor, and thromboxane A 2 receptor. Other features and advantages of the invention will be apparent from the detailed description set forth below, and from the claims. Brief Description of the Drawings Figs. la-Id is a set of graphs illustrating the effect of ACG i2 on G protein activation. (A) Effects of ACG i2 and control peptides on peptide 14-induced G i2 activation. (B) Effect of ACG i2 on TrM-peptide 14-induced G i2 activation and 0III-2-induced G s activation. (C) Effect of ACG i2 on G 1 and G i3 activation. (D) Effect of ACG i2 on Mill-induced G i2 and G Q activation. Figs. 2a-2b is a pair of graphs illustrating the mode of action of ACG i2 . (A) Dose/response relationship of peptide 14 action in the presence of various concentrations of ACG i2 . (B) Effect of ACG i2 on activation of 1 nM G i2 induced by peptide 14. Figs. 3a-3c is a set of graphs illustrating the structure-function relationship of ACG i2 on peptide 14- induced G i2 activation. (A) Effect of ACG i2 and high potency group variants. (B) Effect of low potency group variants. (C) Effect of intermediate potency group variants. Fig. 4 is a bar graph illustrating the effect of ACG i2 on mAChR-G i2 coupling. Fig. 5 is a schematic drawing illustrating a proposed mechanism whereby the activation state of G i2 is affected by peptide 14 and/or ACG i2 peptide. Fig. 6 is a set of three photomicrographs illustrating the inhibitory effect of ACG i2 on serum- induced CHO cell growth. Fig. 7 is an autoradiograph of an SDS-PAGE analysis illustrating the effect of ACG o2 on TGF3-induced fibronectin secretion from kidney cells. Fig. 8 is a pair of photomicrographs illustrating the effect of ACG i2 on cardiac fibrosis in myopathic hamsters. Detailed Description The anticouplones of the invention were discovered by analyzing the sequences of the known G proteins to identify the region on each which was deemed likely to function as an anticouplone, and then testing each candidate anticouplone, and variants thereof, in appropriate in vitro and in vivo assays. Identification of Candidate Anticouplone Sequences On the assumption that, in order to account for the specificity of each receptor for a given type of G protein, the Gα subunit of a given G protein must participate in the direct interaction with the associated receptor's couplone, it was postulated that the anticouplone, or signal-acceptor domain, of the G protein dimer would be located, at least in part, on the Gα subunit. Certain criteria, described below, were then established to define the putative signal-acceptor domain on each G protein's α subunit. These criteria were initially applied to determine the anticouplone of G i2 α, as follows: Although a recent publication suggested otherwise (Okuma et al., J. Biol. Chem. 267:14826-14831, 1992) , a number of lines of evidence indicated to Applicant that at least a portion of the anticouplone sequence would be located at or near the carboxy-terminal end of the G protein (Okamoto et al., Proc. Natl. Acad. Sci. USA 88:3020-8023, 1991; Ui et al.. Adv. Cyclic Nucleotide Protein Phosphorylation Res., 17:145-151, 1984; Rail et al., FEBS Lett. 224:365-371, 1987; Masters et al., Science 241:448-451, 1988; Moss and Vaughan, eds., American Society for Microbiology, 1988, pp.207- 224; Simonds et al., Proc. Natl. Acad. Sci. USA, 86:7809- 7813, 1989; McClue et al., FEBS Lett. 269:430-434, 1990; Shenker et al., J. Biol. Chem. 266:9309-9313, 1991; Murray-Whelan et al., J. Biol. Chem. 267:2960-2965, 1992; Meinkoth et al., J. Biol. Chem. 267:13239-13245, 1992; Okamoto and Nishimoto, Proc. Natl. Acad. Sci. USA 88:8020-8023, 1991; and Sullivan et al., Nature 330:758- 760, 1987) . Therefore, the first criterion specified that the candidate signal-acceptor region be located in the carboxy-terminal portion of G i2 α. Within the carboxy-terminal portion of G i2 α, Applicant focused on the region Asp338-Asp351 (SEQ ID NO: 16) . This region has a primary structure in which the negatively charged residues are oriented as matching the positively charged basic residues essential for the G i2 - activating function of Peptide 14. The structural determinants for this function of Peptide 14 were hypothesized to be (i) two basic residues at its amino terminus and (ii) a carboxy terminal motif of B-B-X-B or B-B-X-X-B . Asp338-Asp351 (DAVTDVIIKNNLKD) (SEQ ID NO: 16) is the only region of G i2 that meets all of these criteria. This sequence was therefore tentatively identified as the G i2 α anticouplone. It was found that G il α contains the same 14 residues at a corresponding region, while G i3 α contains the almost identical sequence DAVTDVIIKNNLKE (SEQ ID NO: 17), in which the N-terminal Asp is replaced by Glu. When the four criteria are applied to G ol α and G o2 oi- , the resulting anticouplone sequences are defined by DAVTDIIIANNLRGC (SEQ ID NO: 8) and DAVTDIIIAKNLRGC (SEQ ID NO: 10) , respectively. The anticouplone sequence of G s is NDCRDIIQRMHLRQY (SEQ ID NO: 12), while that of G g is AAVKDTILQLNLKEY (SEQ ID NO: 14). The above reasoning was used to identify a putative receptor-binding domain on each individual Gα species. Later experiments carried out with synthetic peptides representing these putative receptor-binding domains have suggested that, rather than receptor-binding domains, these particular regions of the Gα polypeptides may serve as Gα-activating regulator regions. This completely unexpected finding is discussed in detail below. Synthesis of Anticouplone Peptides The peptides used in this study were synthesized and purified as described (Okamoto et al., 1990; Okamoto and Nishimoto, 1991; Okamoto et al., 1991a; Okamoto and Nishimoto, 1992) . The following peptides were prepared: 1. ACG i2 , corresponding both to G il α Asp337- Cys351 and to G i2 α Asp338-Cys352 (DAVTDVIIKNNLKDC; SEQ ID NO: 3) . The fact that pertussis toxin, which catalyzes ADP-ribosylation of Cys352, attenuates G i2 activation produced by peptide 14 (Okamoto et al., 1990, supra ) as well as by IGF-IIR (Nishimoto et al., J. Biol. Chem. 264:14029-14038, 1989), prompted the inclusion of Cys352 in this peptide. 2. ACG i3 (DAVTDVIIKNNLKEC; SEQ ID NO: 5). 3. ACG ol (DAVTDIIIANNLRGC; SEQ ID NO: 8). 4. ACG o2 (DAVTDIIIAKNLRGC; SEQ ID NO: 10) . 5. ACG S (NDCRDIIQRMHLRQY; SEQ ID NO: 12) . 6. ACG g (AAVKDTILQLNLKEY; SEQ ID NO: 14). 7. Alternative G O1 peptide NNIQWFDAVTDIIIANNLRGC (SEQ ID NO: 9) . 8. Alternative G o2 peptide NNIQFVFDAVTDIIIAKNLRGC (SEQ ID NO: 11) . 9. Alternative G s peptide DTENIRRVFNDCRDIIQRMHLRQY (SEQ ID NO: 13). 10. Alternative G peptide DTENIRFVFAAVKDTILQLNLKEY (SEQ ID NO: 15). 11. Control peptide Glu297-Asp310 (EAASYIQSKFEKLN; SEQ ID NO: 18) corresponding to G i2 α Glu297-Asp310. 12. Control peptide Lys346-Phe355 (KNNLKDCGLF; SEQ ID NO: 19) , representing the carboxy-terminal 10 residues of G i2 α. 13. ± variant (AAVTDVIIKNNLKDC; SEQ ID NO: 20). 14. A 2 variant (DAVTAVIIKNNLKDC; SEQ ID NO: 21) . 15. A 3 variant (DAVTDVIIKANLKDC; SEQ ID NO: 22) . 16. A 4 variant (DAVTDVIIKNALKDC; SEQ ID NO: 23) . 17. A 5 variant (DAVTDVIIKNNLKAC; SEQ ID NO: 24) . 18. p9 variant (DAVTDVIIK; SEQ ID NO: 25). 19. pll variant (DVIIKNNLKDC; SEQ ID NO: 26). 20. del C variant (DAVTDVIIKNNLKD; SEQ ID NO: 16) 21. Peptide 14 (RVGLVRGEKARKGK; SEQ ID NO: 27), the 14-residue couplone portion of the G i2 -coupled receptor protein IGF-IIR. 22. TrM peptide 14 (LTACLLTLLLYRVGLVRGEKARKGK; SEQ ID NO: 28) , peptide 14 linked to the native transmembrane domain of IGF-IIR. 23. βXτi-2 (RRSSKFCLKEHKALK; SEQ ID NO: 29), the 15-residue couplone region of the G s -coupled receptor /32AR. 24. Mill peptide (RNQVRKKRQMAARERKVTR; SEQ ID NO: 30) , the 19-residue couplone region of the G^G Q -coupled M 4 muscarinic acetylcholine receptor (M 4 AChR) . Designed but not prepared were two additional peptides in the series: 25. Alternative G il /G i2 peptide DTKNVQFVFDAVTDVIIKNNLKDC (SEQ ID NO: 4) , and 26. Alternative G i3 peptide DTKNVQFVFDAVTDVIIKNNLKEC (SEQ ID NO: 6). In Vitro . Cell-free Assays of Anticouplone Peptides Materials and Methods The in vitro assays described below utilize the couplone portion of each of a number of G-coupled receptors, instead of an intact receptor molecule, as a means for activating the corresponding anticouplone or intact G-protein. Except as noted below, G i2 used in this study was trimeric G i2 (i.e., G i2 α/3γ) purified from bovine brain to near homogeneity (Katada et al., FEBS Lett . 213:353-358 (1987), stored in buffer A (20 mM hepes/NaOH (pH 7.4), 1 mM EDTA, and 0.7% CHAPS), and diluted > 10 fold for assays. The G i2 used for the reconstitution experiment was trimeric G i2 purified from bovine spleen to homogeneity and dissolved in buffer B (Morishita et al., 1989) . G i3 α (Morishita et al., Biochem . Biophys . Res . Commun . 172:249-255 (1990), was purified from bovine spleen and used in combination with 1.5-fold concentrated Gβy (Katada et al., 1987). This preparation of G i3 α was 10-20% contaminated by G il α, but not by other G proteins. Trimeric G s and Gβy purified from bovine brain to near homogeneity (Katada et al., 1987) were also stored in buffer A. mAChR (muscarinic acetylcholine receptor) was purified from porcine brain to near homogeneity (Haga et al., 1986) and dissolved in 0.5 M potassium phosphate buffer (pH 7.0) containing 0.1% digitonin. This receptor preparation was reconstituted with G i2 in phospholipid vesicles using a gel filtration method as described previously (Nishimoto et al., 1989). The concentrations of mAChR and G i2 in the vesicles were 6.9 nM and 29 nM, respectively. GTPγS binding Assay - GTPγS binding to G proteins was assayed at 37°C in 20 mM Hepes/NaOH buffer (pH 7.4) containing 130 μM MgCl 2 , 110 μM EDTA and 60 nM [ 35 S]GTPγS, as described previously (Okamoto et al., 1990) . GTPγS binding to polypeptides was negligible. The total amount of G protein was measured as maximal GTPγS binding at room temperature, as described (Okamoto et al., Cell 67:723-730, 1991a). [ 35 S]GTPγS was purchased from DuPont- New England Nuclear. Binding of GTPγS to G proteins obeyed first-order kinetics according to the equation ln[ (BT - B) /B τ = -k t , where B is the binding at time t and B τ is the total binding observable at an infinite time. Thus, the apparent first-order rate constant for GTPγS binding (k app ) , which is equal to the slope of the tangent to the GTPγS binding curve at time 0 and represents the actual GTPγS binding rate, was calculated from this equation. Results In the experiment illustrated in Fig. 1A, lOnM G i2 was incubated with 30 M peptide 14 (RVGLVRGEKARKGK; SEQ ID NO: 27) , the couplone portion of the IGF-II receptor, in the presence of various concentrations of (D) ACG i2 (DAVTDVIIKNNLKDC; SEQ ID NO: 3) , (♦) the control G i2 α Glu297-Asp310 peptide (EAASYIQSKFEKLN; SEQ ID NO: 18) , or (o) the control G i2 α Lys346-Phe355 peptide (KNNLKDCGLF; SEQ ID NO: 19) for 5 min under the GTPγS binding assay conditions described above, and GTPγS binding to G proteins was measured. The effect of ACG i2 on G i2 in the absence of peptide 14 is indicated by ■. Percent stimulation of GTPγS binding was calculated by subtracting the basal fractional binding and dividing by the stimulated fractional binding observed in the absence of ACG i2 . The basal fractional binding (= 0%) was 0.39 mol GTPγS binding/ ol G^S min (5 min -1 ) . The 100% increase represents the GTPγS binding of 0.85 (5 min -1 ) . Values in all figures represent the mean ± S.E. of three experiments. Fig. 1A shows that ACG i2 peptide at 30 M inhibits binding of GTPγS to G i2 in the presence of peptide 14 to the basal level of binding exhibited by G i2 in the absence of peptide 14. The IC 50 was «3μM. ACG i2 had no effect on GTPγS binding to G i2 in the absence of peptide 14. G i2 α has another region that satisfies (I)-(III) : residues Glu297-Asn310 (EAASYIQSKFEKLN; SEQ ID NO: 18) . This peptide, however, showed no effect on peptide 14-induced G i2 activation. As another control, a peptide representing the carboxy-terminal 10 residues of G i2 α (KNNLKDCGLF; SEQ ID NO: 19) was synthesized and tested in this assay. Unlike ACG i2 , this decapeptide exhibited no inhibitory effect on peptide 14-induced G i2 activation. These findings suggest that the antagonizing effect of ACG i2 on G i2 activation is attributable to the specific amino acid sequence of the peptide. Transmembrane domain-connected peptide 14 ["TrM- peptide 14"; LTACLLTLLLYRVGLVRGEKARKGK (SEQ ID NO: 28)] is peptide 14 that is linked to the native transmembrane domain of IGF-IIR. It has been demonstrated that, in phospholipid vesicles, TrM-peptide 14 can interact with G i2 in a manner more similar to that of the native holo receptor than can peptide 14 (Okamoto et al., 1990). In one of the experiments shown in Fig.IB, 0.3 nM G i2 reconstituted in phospholipid vesicles with lOOnM TrM- peptide 14 was exposed to various concentrations of ACG i2 , and GTPγS binding was measured (♦) . The basal fractional GTPγS binding to G i2 in this experiment was 0.39 (5 min " λ ) , and the 100% binding level was 0.88 (5 min -1 ) . ACG i2 completely blocked the stimulatory effect of 100 nM TrM- peptide 14, with an IC 50 of 3 μM (Fig. IB). Thus, even where the context more closely approximates the native environment of the G protein than in the experiment shown in Fig.lA, ACG i2 effectively blocks the stimulatory effect of the couplone on G i2 with the same potency and efficacy as observed in the latter experiment. The effect of ACG i2 on βIII-2-induced G s activation is shown in Fig.IB (D) . GTPγS binding was measured following incubation of solubilized G s at lOnM with lμM 0III-2 (RRSSKFCLKEHKALK; SEQ ID NO: 29) in the presence of ACG i2 for 10 min. The basal fractional GTPγS binding to G s was 0.30 (10 min -1 ) , and 100% binding was 0.60 (10 min -1 ). ACG i2 had no effect at lμM. Unlike inhibition of stimulation of G i2 , which reaches 100% at 3μM ACG i2 , the maximal inhibition of /3III-2-stimulated G s by ACG i2 was only 40%, reflecting the fact that the G s anticouplone is not identical to ACG i2 , and so the latter peptide binds to the G s -coupled receptor relatively inefficiently. At higher concentrations, ACG i2 proved to have a positive rather than inhibitory effect on G s stimulation. The region of G Ξ α that is comparable to the ACG i2 region of G i2 α in topographical structure was synthesized; this region is defined by Asn384-Tyr398 of G s α (NDCRDIIQRMHLRQY; SEQ ID NO: 12) . At concentrations ranging up to 100 μM, this peptide (ACG S ) had no effect at all on peptide 14-induced G i2 activation, again reflecting the specificity of each anticouplone (data not shown) . Peptide 14 is capable of activating G 1 and G i3 as well as G i2 (Okamoto et al., 1990). The effect of ACG i2 on peptide 14-induced activation of these G.^ proteins was examined as follows: 10 nM G 1 (□) or G i3 (♦) was incubated with 30 μM peptide 14 in the presence of various concentrations of ACG i2 for 4 min, and GTPγS binding was measured. The fractional GTPγS binding to G L1 or G i3 at 0% was (in 4 min -1 ) 0.38 or 0.30, and that at 100% was 0.54 or 0.63, respectively. Surprisingly, ACG i2 had relatively little effect on G L1 activation (Fig. 1C) . Even high concentrations (> 30 μM) of ACG i2 maximally inhibited G il activation by only 30%. The G L1 preparation used had trace contamination by G 0 , as described (Katada et al., FEBS Lett . 213:353-358 (1987). Since the region of G iα α comparable to ACG i2 has a sequence identical to ACG i2 , as mentioned above, it appears this region on G il α does not possess the same function as the identical region on G i α. Fig. 1C also shows the effect of ACG i2 on peptide 14-induced G i3 activation. ACG i2 maximally inhibited G i3 activation by «60%. This suggests that ACG i2 has an antagonizing effect on G L protein activation in the order of G i2 > G i3 >G il . These results indicate that the ACG i2 peptide blocks G i2 activation in a selective manner. The Mill peptide is a G^G Q -activator region in the third intracellular loop of the G-coupled receptor termed M 4 AChR (Okamoto et al., J. Biol. Chem. 267:8342- 8346, 1992) . This peptide has the sequence RNQVRKKRQMAARERKVTR (SEQ ID NO: 30) . In the experiments illustrated in Fig. ID, 10 nM G Q (D) or G i2 (♦) was incubated with 1 μM Mill for 2 or 5 min, respectively, and GTPγS binding was measured in the same manner as in Fig. 1A. The fractional GTPγS binding to G 0 at 0% and 100% was 0.36 and 0.86 (2 min -1 ), respectively, and that to G i2 at 0% and 100% was 0.30 and 0.96 (5 min -1 --, respectively. Mill-induced G i2 activation was found to be attenuated by ACG i2 in a dose-dependent manner, with an IC 50 of 10 μM (Fig. ID) . ACG i2 can therefore inhibit G i2 activation caused by the effector peptides of m 4 AChR and IGF-IIR with similar potencies. In contrast, ACG i2 had no effect on Mill-induced G 0 activation at < 10 μM, and its effect on Mill-induced G Q activation at higher concentrations (IC 50 «30 μM) was significantly («3 times) less potent than its effect on Mill-induced G i2 activation. This provides strong evidence that ACG i2 acts on G proteins rather than on receptor peptides. To verify the notion that ACG i2 acts on G i2 itself, and not on receptor sequences, two series of experiments were performed. First, the dose-response curve for peptide 14 action on G i2 in the presence of various concentrations of ACG i2 was generated (Fig. 2A) . Following incubation of 10 nM G i2 with various concentrations of peptide 14 in the absence (D) or presence of 10 μM (♦) or 30 μM (!) ACG i2 for 5 min, GTPγS binding was assayed; fractional GTPγS binding to G i2 is indicated in the figure. As the concentration of ACG i2 increased, the efficacy of peptide 14 action was found to be decreased. This suggests that ACG i2 does not compete with G i2 for peptide 14. The second series of experiments investigated the effect of ACG i on lower concentrations of G i2 that had been activated by peptide 14 to the same extent (Fig. 2B) . InM G i2 was incubated for 5 min with 3 μM peptide 14 in the presence of various concentrations of ACG i2 , and GTPγS binding was measured. The fractional GTPγS binding at 0% and 100% in this experiment was 0.40 and 0.55 (5 min -1 ), respectively. As shown in Fig. 2B, the IC 50 of the ACG i2 effect on the activation of 1 nM G i2 was ~3μM, which is identical to the IC 50 observed with lOnM G i2 . If one assumes that ACG i2 inhibits G i2 activation by acting on receptor sequences, the antagonizing effect of ACG i2 on smaller amounts of G i2 at a similar intensity of peptide 14 stimulation would be observed at lower concentrations of ACG i2 , resulting in a lower IC 50 . Conversely, if ACG i2 acts on G i2 , the potency of the ACG i2 effect on smaller compared to larger amounts of G i2 would not be altered, because the affinity of G i2 for ACG i2 would presumably determine the potency of ACG i2 . Therefore, the present results suggest that ACG i2 inhibits peptide 14/G i2 coupling by acting on G i2 with constant affinity. By examining the relationship between the structure of ACG i2 and its function in the inhibition assay described above, it was possible to determine the primary structure essential for the inhibitory action of ACG i2 . In the experiments shown in Figs. 3a-3c, G i2 at 10 nM was incubated with 30 μM peptide 14 in the presence of various concentrations of ACG i2 or one of its structural variants, and GTPγS binding to G i2 was measured. The sequence of each peptide is indicated above the graphs (a bar indicates the same sequence as intact ACG i2 ) . The 0% and the 100% increases, which correspond to the basal and peptide 14-stimulated fractional GTPγS binding to G i2 , were similar to those described in Fig. 1A. These groups can be practically classified according to the inhibition observed at 10 μM. The high potency peptides of the first group (Fig. 3A) display > 80% inhibition at lOμM concentration; these peptides are the A 2 variant (DAVTAVIIKNNLKDC; SEQ ID NO: 21) , in which the Asp at position five is replaced by Ala, and the A 5 variant (DAVTDVIIKNNLKAC; SEQ ID NO: 24) , in which the Asp at position 14 is replaced by Ala. The second, low potency group (Fig. 3B) displays < 30% inhibition at 10 μM, and is made up of the λ variant (AAVTDVIIKNNLKDC; SEQ ID NO: 20) , in which the Asp at position 1 is replaced by Ala; the A 3 variant (DAVTDVIIKAN KDC; SEQ ID NO: 22), in which the Asn at position 10 is replaced with Ala; the p9 variant (DAVTDVIIK; SEQ ID NO: 25) , in which the carboxy- terminal 6 residues of ACG i2 are deleted; and the del C variant (DAVTDVIIKNNLKD; SEQ ID NO: 16), in which the C- terminal Cys is deleted from ACG i2 . The third, intermediate potency group (Fig. 3C) consists of the A 4 variant (DAVTDVIIKNALKDC; SEQ ID NO: 23), in which the Asn at position 11 is replaced by Ala; and the pll variant (DVIIKNNLKDC; SEQ ID NO: 26), in which the amino- terminal 4 residues are deleted. These results suggest that the extreme a ino- terminal Asp, the Asn residues at positions 10 and 11, and the carboxy-terminal Cys are essential for the inhibitory activity of ACG i2 , and that, since both the amino-terminal residue and the carboxy-terminal residue of ACG i2 are required, the segment of G i2 α represented by ACG i2 corresponds to the minimal anticouplone domain of G i2 α. In contrast, the Glu residues at positions 2 and 14 appear to be dispensable. One can conclude from this information that, contrary to the primary hypothesis used for the initial search that anionic residues on G i2 α would interact with the basic residues of peptide 14, all of the negatively charged residues are unlikely to be oriented facing the basic residues of peptide 14 or Mill, or at least that such a matchup of anionic and basic residues is not of critical importance at some of the sites. It remains unclear how the Cys 352 residue of ACG i2 plays a key role. To determine whether ACG i2 uncouples G i2 from the signals of intact receptors as well as from the signals of their effector peptides, the effects of ACG i2 in mAChR- G i2 reconstituted phospholipid vesicles studied (Fig. 4) . In these vesicles, the basal value of rate constant kapp of GTPγS binding to G i2 in the absence of acetylcholine was 0.112 ± 0.005 (min-1) ; 10 mM acetylcholine (for 20 min at 30°C) increased the k value to 0.286 ± 0.082. The magnitude of the acetylcholine effect is similar to that previously reported (Kurose et al. , J. Biol. Chem. 261:6423-6428, 1986) . When 10 mM acetylcholine was incubated with the vesicles in the presence of 30 μM ACG i2 , the k p value of GTPγS binding to G i2 was found to be 0.157 ± 0.013. This indicates that the G i2 activation induced by acetylcholine in AChR-G i2 vesicles was a 75% inhibited by ACG i2 . ACG i2 - induced inhibition was saturated at 30 μM (data not shown) . ACG i2 had no significant effect on basal G i2 activity in the absence of acetylcholine (Fig. 4) . A model illustrating the possible way in which ACG i2 blocks the interaction of G i2 and Peptide 14 is shown in Fig. 5. It is postulated that the anticouplone portion of G i2 α acts on a hypothetical second site of G i2 α itself, thereby stabilizing G i2 α in the unstimulated state (Fig. 5, left) . Peptide 14, which has the sequence of the effector (couplone) region of IGF-IIR, binds to the contact site on G i2 α, resulting in a conformational change in G i2 a that diminishes the accessibility of the anticouplone region of G i2 α to the hypothetical second site on G i2 α; this leads to a decrease in binding of the two regions of G i2 α and a concomitant activation of the G protein (Fig. 5, upper right) . Addition of ACG i2 peptide causes the hypothetical second site on G i2 α to be occupied regardless of the presence or absence of Peptide 14, thereby stabilizing G i2 α in the inactive state in a manner that is independent of (and so does not compete with) G i2 α binding to Peptide 14. Although the receptor-contact site is suggested to be different than the ACG i2 region of G i2 α in this figure, it should be emphasized that they are not necessarily different. Furthermore, it is noted that in the actual intracellular environment, there are other factors (e.g., nucleotide-binding status, GTP hydrolytic activity, and association with G/3γ) that critically affect the equilibrium of each step. Because ACG i2 has different effects on the various G proteins (see above) , it is unlikely that the hypothetical second site resides on G3γ (which is identical for all of the G proteins) rather than Gα (which is G-protein-specific) . Cell-based Assays Inhibition of somatostatin receptor function . It is known that somatostatin induces K + channel activation in a manner sensitive to pertussis toxin in human growth hormone-secreting tumors (Yamashita et al., Am. J. Physiol. 253:E28-E32, 1987) . The effect of each of ACG i2 , ACG i3 , ACG S , ACG ol , and ACG o2 on somatostatin-induced K + currents in human pituitary cells was measured using the patch clamp technique, as described below. Three human growth hormone-secreting pituitary adenomas were obtained at transsphenoidal surgery. The tissue was minced into small pieces (less than 1 mm in diameter) and was treated with 1000 units/ml dispase (Wako, Japan) . These dissociated cells (»10 5 cells/ml) were seeded onto 35-mm culture dishes. The monolayer cells were cultured at 37°C under 5% C0 2 in humidified air in Delbecco's modified Eagle's medium (DMEM) containing 10% heat-inactivated FCS. Electrophysiological experiments were done within 4 weeks after cell preparation. A whole cell variation of the patch electrode voltage clamp technique was used to record membrane currents (Ha ill et al., Pflϋger Arch. 391:85-100, 1987) . The patch electrode solution contained 95 mM potassium aspartate, 47.5 mM KC1, 1 mM MgCl 2 , 5.0 mM EGTA (potassium salt), 10 mM HEPES/KOH (pH 7.2), 2 mM ATP and 0.1 mM GTP. One of the anticouplone peptides, dissolved in distilled water, was mixed with the patch electrode solution to a final concentration of 100 μM, and was introduced into the interior of a pituitary cell in accordance with the published method. The extracellular medium, composed of 125 mM NaCl, 5 mM KC1, 1 mM MgCl 2 , 2.5 mM CaCl 2 , and 10 mM HEPES/NaOH (pH 7.4), was continuously perfused around the test cell during recording, using a peristaltic pump, and 10 -7 M somatostatin was introduced by changing the perfused medium. The liquid junction potential between the extracellular solution and the internal solution was directly measured using a 3 M KC1 electrode as a reference. The value of the liquid junction potential (- 8 mV) was corrected in each experiment. Glass capillaries of 1.5 mm diameter with a filament were used to fabricate an electrode for the whole cell clamp. They were coated with Sylgard and fire-polished before use. The patch electrode resistance used in these studies was in the range of 5 to 8 MΩ. The seal resistance was over several tens of GΩ. A List EPC-7 amplifier was used for the membrane current and potential. Application of voltage or current pulse, data acquisition, and analysis were done with a Gateway 2000 computer using the pCLAMP program (Axon Instruments, CA) . All experiments were performed at room temperature (22-25°C) . The intracellular solution that filled the inside of the pipet portion of the apparatus contained one of the following anticouplone peptides at 100 μM: ACG i2 , ACG i3 , ACG S , ACG ol , or ACG o2 . The exterior of the cell was bathed with the extracellular solution containing 100 nM somatostatin while the outward K + current was monitored. In the absence of anticouplone peptides, somatostatin induces approximately 20 pA K + current over baseline. This somatostatin-induced current level is not affected by the presence of 100 μM ACG i3 , ACG S , ACG ol , or ACG o2 . ACG i2 , however, abolished the somatostatin-induced increase in K + current, reducing the measured current to the baseline level observed in the absence of somatostatin. These data suggest that G i2 , but not G i3 , G s , G ol , or G o2 , is involved in the somatostatin receptor/K + channel linkage, and that ACG i2 can specifically inhibit the ability of the somatostatin receptor to act on ion channels. Since this function of the somatostatin receptor on endocrine cells is related to the inhibition of hormone secretion by such cells, modulation of this receptor/G protein system by ACG i2 permits the control of hormone secretion from endocrine cells. Inhibition of cellular growth . G i2 α has been shown to be an oncogene in certain human tumors (Lyons et al, Science 249:655-659, 1990) . The effect of the peptide ACG i2 on the growth of CHO cells was measured as follows: CHO cells were grown in Ham F12 medium (GIBCO) plus 10% fetal calf serum (FCS) . Once they reached at least 80% confluency, the cells were incubated with Ham F12 plus 0.5% FCS for 24 hours. They were then incubated for an additional 24 hours with Ham F12 plus 10% FCS in the presence of BUdR and various concentrations of ACG i2 . The cells were then fixed and the BUdR incorporated into their nuclei was labeled in accordance with the instructions included with the cell proliferation detection kit (RPN.210, Amersha ) . Fig. 6 shows the relative extent of BUdR incorporation into cells in the presence of no ACG i2 (top photograph) , lOμM ACG i2 (center photograph) , or 100 μM ACG i2 (bottom photograph) , wherein a labelled nucleus signifies a proliferating cell. It can be seen that FCS-induced proliferation of CHO cells is inhibited by ACG i2 in a dose-dependent fashion, with 10 μM ACG i2 producing significant inhibition and 100 μM inhibiting labelling almost completely. This suggests that ACG i2 may have value as an anti-growth or anti-cancer reagent. Inhibition of TGFβ-induced matrix formation . The secretion of matrix proteins (in particular, fibronectin) by kidney, lung and liver cells may lead to sclerosis of those organs. Transforming growth factor-/3 (TGFβ ) , which stimulates the secretion of fibronectin, may therefore contribute to such sclerosis. Since the TGF3 receptor is a G o2 -coupled receptor, the ability of ACG o2 to inhibit the TGF3-induced stimulation of fibronectin secretion by NRK (rat renal fibroblast) cells (Ignotz and Massague, J. Biol. Chem. 261:4337-4345, 1986) was assayed. NRK cells were cultured in RPMI 1640 supplemented with 5% FCS in a C0 2 -incubator at 37°C. The medium was replaced every two days. Cells were regularly subcultured by trypsin-EDTA before reaching confluency. In the experiments described below, the cells were grown in monolayer to confluency in 6-well culture plates (Corning, NY) , then incubated for 12 hours with RPMI 1640 plus 0.5% FCS, and for a further 12 hours with RPMI 1640 plus 0.5% FCS in the presence or absence of 50 pM TGFβ (R & D System, Minneapolis, MN) , to which was added 100 μM ACG i2 , ACG S , ACG o2 , or ACG . The medium from each well was collected and frozen at -20 o C until assay. Fibronectin secreted into each sample of medium was assessed by immunoblot as follows: Each medium sample was mixed with an equal volume of 2x concentrated Laemmli buffer (Laemmli, Nature 227:680-685, 1970), and boiled at 90°C for 5 min. Proteins were separated by electrophoresis on 7.5% SDS- polyacrylamide gel, and then transferred to a polyvinylidene difluoride sheet (Immobilon-P, Millipore) by electroelution at 0-4°C with constant voltage of 75 V for 8 hours. After transfer, the sheet was incubated with PBS containing 5% bovine serum albumin and 2% skim milk (Defco) overnight at room temperature to block nonspecific protein binding. The sheet was then incubated with PBS containing 0.1% bovine serum albumin and an anti-fibronectin antibody (Chemicon International, CA) at a final concentration of 0.5 mg/ml for 3 hours at room temperature. After washing with ice-cold PBS/0.05% Tween 20 three times, the sheet was incubated with 0.04 units/ml of a horseradish peroxidase-conjugated anti-rabbit IgG (Sigma, A-8257) in PBS/0.1% bovine serum albumin for 3 hours at room temperature. The sheet was washed six times with ice-cold PBS/0.05% Tween 20, incubated with ECL (Enhanced ChemiLuminescence) solution (Amersham, RPN 2101) according to instructions for 1 min, and exposed on Kodak XAR5 film for 40-60 seconds. As shown in Fig. 7, a significant amount of fibronectin is secreted by the cells exposed to TGF3, whether or not any of ACG i2 , ACG S , or ACG is present in the culture medium. In contrast, those cells exposed to TGF3 in the presence of ACG o2 secrete relatively little fibronectin. This indicates that ACG o2 can inhibit the TGF3-induced secretion of fibronectin by these cells, suggesting that ACG o2 has use as a therapeutic for the inhibition of organosclerosis, as well as of TGF3 activity in general. Inhibition of T cell receptor function with ACG q . T cell receptor stimulation by monoclonal antibody OKT 3 in Jurkat cells, a line of human T cells, induces measurable polyphosphoinositide (PI) turnover. 10 7 cells were labelled with 5μCi/ml [ 3 H]myoinositol in inositol- free RPMI1640 for 12 hours. After incubating the cells with 500 μM ACG g , samples containing 5xl0 5 cells were then exposed to the monoclonal antibody OKT 3 (Ortho) at 1:100 dilution for 5 min. Perchloric acid was added to a final concentration of 10% to lyse the cells and terminate the reaction. Cell lysates were collected into tubes and brought to pH> 8 by the addition of KOH. Following centrifugation of the lysates, the supernatants were passed over a DOWX anion exchange column (Muromachi Chemicals, Japan) to separate inositol polyphosphates (IPs) from other inositol metabolites, and the amount of [ 3 H] label in the inositol trisphosphate (IP 3 ) fraction assessed. Cells exposed to 0KT 3 incorporated [ 3 H] into IP to a level 157% that of the control cells (cells not exposed to OKT 3 ) , reflecting the stimulatory effect OKT 3 has on PI turnover in T cells. When the cells pretreated with 500 μM ACG were stimulated with OKT 3 , the level of [ 3 H] incorporation into IP 3 was only 112% that of the unstimulated control cells; in contrast, pretreatment with 500 μM ACG i2 did not inhibit stimulation of the cells by OKT 3 . These results indicate that ACG , can block the function of the T cell receptor, suggesting a use of this anticouplone peptide as an immunosuppressant. In vivo Assay of Anticouplone Peptides Myopathic Syrian hamsters BIO 53.58 spontaneously develop fibrosis of the heart muscle (i.e., development of extraneous collagen fibers that eventually interfere with muscle function) by about 16 weeks of age, and as such are used as models for the human disease cardiomyopathy. In the experiment reported herein, 10- week-old BIO 53.58 hamsters received intraperitoneal injections with 5 μl of 10 mM ACG g , 10 mM ACG i2 , or physiological saline once a week for 6 weeks. The animals were then decapitated and their hearts were excised, fixed in 10% formaldehyde solution, and cut horizontally at the level of the papillary muscle to make sections for light microscopy. The muscle sections were stained with sirius red (which specifically stains collagen) , and evaluated under the microscope. In each photomicrograph shown in Fig. 8, the right ventricular free wall is located at the left of the photomicrograph and the interventricular septum is on the right. As shown in Fig. 8, top panel, the control hamsters exhibited a significant amount of heart muscle fibrosis (indicated by darkly stained lines) . In contrast, the animals treated with ACG i2 for six weeks had remarkably diminished collagen fiber formation (Fig. 8, bottom panel) . Hamsters which received ACG had undiminished, control levels of fibrosis (data not shown) . Use Each of the anticouplone peptides of the invention may be used as a therapeutic for appropriate indications. ACG i2 may be used where inhibition of G L1 - or G i2 -coupled receptor function is desired: for example, to treat neuromuscular diseases and cardiac arrythmia by inhibiting muscarinic acetylcholine receptors; to alleviate dwarfism by inhibiting stimulation of somatostatin receptors on pituitary cells; to block cancerous cell proliferation (or other undesired cell growth, such as cardiomyopathy) by inhibiting the G i2 oncogene; to treat organofibrosis by inhibiting TGF/3 receptors; and to treat malignant hypercalcemia by inhibiting the parathyroid/parathyroid-related protein (PTH/PTHrp) receptor. ACG i3 would be useful for treatment of conditions related to organization and polarization of cells and cellular structures, as during organ development. ACG ol will inhibit stimulation of the nerve growth factor receptor (NGFR) , the activity of which is thought to affect neuronal growth. ACG o2 is useful for inhibiting the TGF/3-induced stimulation of fibronectin secretion which leads to fibrosis and sclerosis of organs such as kidney, lung and liver. Inhibition of TGF/3 is also useful in controlling the generation of cancer clones and in treating glomeronephritis. In addition, ACG o2 can be used to prevent cancer cell growth attributable to abnormal stimulation of the cells by a mutant G o2 oncogene. Because G q is thought to be the G protein to which the T cell receptor is coupled, ACG q would be useful for inhibiting the function of this receptor, and thus the activation of T cells. This anticouplone therefore may be used as an immunosuppressant, such as in organ and bone marrow transplant recipients, and to treat autoimmune disease. ACG g also has potential as a treatment for AIDS, by inhibiting the abnormal signalling that results from binding of HIV gpl20 to CD4 on the T cell surface. In addition, ACG , which inhibits signalling through the angiotensin receptor, may be used as a treatment for hypertension. G s -coupled receptors include the glucagon receptor, the /3 2 AR, and the PTH/PTHrP receptor. ACG S could therefore be utilized as a treatment for diabetes, hypertension, and malignant hypercalcemia. Because a mutant form of G s acts constitutively in some pituitary tumors, ACG S could be used to treat such pituitary tumor- related conditions as giantism and secondary menopause. The treatment protocol to be used for any one of the above indications could be readily determined by one of ordinary skill in the art of pharmacology, given the teachings set forth above. The peptides of the invention may be administered by a standard method such as intravenous, intraperitoneal, intramuscular, or subcutaneous injection, and may be administered in a single dose, several doses spread over time, or a continuous infusion. The dosage will vary with the age and condition of the patient and the particular condition being treated, but is expected to be in the range of 0.5μg/kg/day to 50 mg/kg/day. A dosage which results in a concentration at the target site of approximately 10- lOOμM would be an effective dose consistent with the experimental results provided above. Incorporating the peptides into micelles or liposomes may improve delivery into cells. Other Embodiments Other embodiments are within the claims set forth below. For instance, many other receptors are known or believed to be G-coupled receptors, based in part on the their distinctive arrangement of multiple transmembrane domains known to be typical of G-coupled receptors; inappropriate signalling through these receptors can be controlled by the peptides of the invention. An example is the thyroid-stimulating hormone (TSH) receptor, overstimulation of which (e.g. , by a receptor-specific antibody) leads to hyperthyroidism, or Basedow's disease. This receptor is probably a G s -coupled receptor. Another example is the G protein-coupled insulin receptor, which may be overstimulated in a patient with an insulin- secreting tumor. As described above, some amino acid residues within the defined anticouplone sequences can be replaced with other residues, with no significant loss of biological activity. For example, in ACG i2 , an Asp→Ala substitution at position 5 or 14 may be made with little or no loss of activity, while similar nonconservative substitutions at positions 1, 10, and 11 resulted in a significant loss of activity in the in v^tro assay used. In general, conservative substitutions in which the relative charge of the residue occupying the substituted position does not vary (i.e., replacing an anionic residue with another anionic residue, or a hydrophobic residue with another hydrophobic residue, etc.) will have less effect on the biological activity of the resulting peptide than will nonconservative substitutions. While deletion of some residues may well not affect biological activity significantly, it is known from the work described above that the residues in both the first and the last (15th) positions of ACG i2 are important for activity of that anticouplone. Variants of the anticouplone peptides utilized in the above experiments can be readily made by one of ordinary skill in the art of peptide synthesis, using standard methods of automated synthesis; each such peptide can then be tested in one or more of the biological assays described above. The in vitro , cell-free assays are particularly suited to testing large numbers of such peptides quickly and efficiently, permitting one to produce and evaluate hundreds of peptide variants without undue experimentation. Thus, the invention is meant to include any peptide which (a) has at least 70% sequence identity with one of the anticouplone peptides described above (preferably at least 85%) , and (b) has at least 80% of the biological activity of the anticouplone peptide which it most closely resembles, in any of the biological assays described above in which that anticouplone peptide has been shown to be active. Of course, a peptide which includes the sequence of one of the anticouplones described above, plus additional sequence (including but not limited to sequence derived from the G-protein of which the anticouplone is a part) , would be expected to have undiminished biological activity compared to the anticouplone itself, provided that the peptide is not too bulky or too highly charged to pass through the cellular membrane as readily as does the anticouplone peptide. Again, such longer peptides can be easily prepared and tested as described. Examples of such longer peptides are presented above as "alternative" anticouplone peptides, shown as SEQ ID NOs: 4, 6, 9, 11, 13, and 15. Also within the invention are analogs of the above peptides, in which one or more peptide bonds have been replaced with an alternative type of covalent bond (a "peptide mimetic") which is not susceptible to cleavage by peptidases. While the in vivo results described above suggest that proteolytic degradation of the peptides following injection into the subject animal may not be a problem, it may be that for certain of the peptides, replacement of a particularly sensitive peptide bond with a noncleavable peptide mimetic will make the resulting compound more stable and thus more useful as a therapeutic. Such mimetics, and methods of incorporating them into polypeptides, are well known in the art. Similarly, the replacement of an L-amino acid residue of the anticouplone peptide with the corresponding D-amino acid residue is a standard way of rendering the polypeptide less sensitive to proteolysis. Also useful in this regard are amino-terminal blocking groups such as t-butyloxycarbonyl, acetyl, ethyl, succinyl, methoxysuccinyl, suberyl, adipyl, azelayl, dansyl, benzyloxycarbonyl, fluorenylmethoxycarbonyl, methoxyazelayl, methoxyadipyl, methoxysuberyl, and 2,4- dinitrophenyl. Blocking the charged amino- and carboxy- termini of the peptides would have the additional benefit of enhancing passage of the peptide through the hydrophobic cellular membrane and into the cell. SEQUENCE LISTING (1) GENERAL INFORMATION: (i) APPLICANT: Nishimoto, Ikuo (ii) TITLE OF INVENTION: REGULATOR REGIONS OF G PROTEINS (iii) NUMBER OF SEQUENCES: 34 (iv) CORRESPONDENCE ADDRESS: (A) ADDRESSEE: Fish & Richardson (B) STREET: 225 Franklin Street (C) CITY: Boston (D) STATE: Massachusetts (E) COUNTRY: U.S.A. (F) ZIP: 02110-2804 (v) COMPUTER READABLE FORM: (A) MEDIUM TYPE: 3.5" Diskette, 1.44 Mb (B) COMPUTER: IBM PS/2 Model 50Z or 55SX (C) OPERATING SYSTEM: MS-DOS (Version 5.0) (D) SOFTWARE: WordPerfect (Version 5.1) (vi) CURRENT APPLICATION DATA: (A) APPLICATION NUMBER: 08/019,073 (B) FILING DATE: February 18, 1993 (C) CLASSIFICATION: (vii) PRIOR APPLICATION DATA: (A) APPLICATION NUMBER: (B) FILING DATE: (viii) ATTORNEY/AGENT INFORMATION: (A) NAME: Clark, Paul T. (B) REGISTRATION NUMBER: 30,162 (C) REFERENCE/DOCKET NUMBER: 00786/146001 (ix) TELECOMMUNICATION INFORMATION: (A) TELEPHONE: (617) 542-5070 (B) TELEFAX: (617) 542-8906 (C) TELEX: 200154 (2) INFORMATION FOR SEQUENCE IDENTIFICATION NUMBER: 1: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 15 (B) TYPE: amino acid (C) STRANDEDNESS: (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 1: Asp Xaa Xaa Xaa Xaa Val lie lie Lys Asn Asn Leu Xaa Xaa Cys 1 5 10 15 (2) INFORMATION FOR SEQUENCE IDENTIFICATION NUMBER: 2: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 15 (B) TYPE: amino acid (C) STRANDEDNESS: (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 2: sp Ala Val Thr Xaa Val lie lie Lys Asn Asn Leu Lys Xaa Cys 1 5 10 15 (2) INFORMATION FOR SEQUENCE IDENTIFICATION NUMBER: 3: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 15 (B) TYPE: amino acid (C) STRANDEDNESS: (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 3: sp Ala Val Thr Asp Val lie lie Lys Asn Asn Leu Lys Asp Cys 1 5 10 15 (2) INFORMATION FOR SEQUENCE IDENTIFICATION NUMBER: 4: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 24 (B) TYPE: amino acid (C) STRANDEDNESS: (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 4: sp Thr Lys Asn Val Gin Phe Val Phe Asp Ala Val Thr Asp Val lie 1 5 10 15 ie Lys Asn Asn Leu Lys Asp Cys 20 (2) INFORMATION FOR SEQUENCE IDENTIFICATION NUMBER: 5: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 15 (B) TYPE: amino acid (C) STRANDEDNESS: (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 5: Asp Ala Val Thr Asp Val lie lie Lys Asn Asn Leu Lys Glu Cys 1 5 10 15 (2) INFORMATION FOR SEQUENCE IDENTIFICATION NUMBER: 6: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 24 (B) TYPE: amino acid (C) STRANDEDNESS: (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 6: Asp Thr Lys Asn Val Gin Phe Val Phe Asp Ala Val Thr Asp Val lie 1 5 10 15 lie Lys Asn Asn Leu Lys Glu Cys 20 (2) INFORMATION FOR SEQUENCE IDENTIFICATION NUMBER: 7: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 15 (B) TYPE: amino acid (C) STRANDEDNESS: (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 7: sp Ala Val Thr Xaa lie lie lie Ala Xaa Asn Leu Arg Xaa Cys 1 5 10 15 (2) INFORMATION FOR SEQUENCE IDENTIFICATION NUMBER: 8: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 15 (B) TYPE: amino acid (C) STRANDEDNESS: (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 8: Asp Ala Val Thr Asp lie lie lie Ala Asn Asn Leu Arg Gly Cys 1 5 10 15 (2) INFORMATION FOR SEQUENCE IDENTIFICATION NUMBER: 9: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 22 (B) TYPE: amino acid (C) STRANDEDNESS: (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 9: Asn Asn lie Gin Val Val Phe Asp Ala Val Thr Asp lie lie lie Ala 1 5 10 15 Asn Asn Leu Arg Gly Cys 20 (2) INFORMATION FOR SEQUENCE IDENTIFICATION NUMBER: 10: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 15 (B) TYPE: amino acid (C) STRANDEDNESS: (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 10: Asp Ala Val Thr Asp lie lie lie Ala Lys Asn Leu Arg Gly Cys 1 5 10 15 (2) INFORMATION FOR SEQUENCE IDENTIFICATION NUMBER: 11: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 22 (B) TYPE: amino acid (C) STRANDEDNESS: (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 11: Asn Asn lie Gin Phe Val Phe Asp Ala Val Thr Asp lie lie lie Ala 1 5 10 15 Lys Asn Leu Arg Gly Cys 20 (2) INFORMATION FOR SEQUENCE IDENTIFICATION NUMBER: 12: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 15 (B) TYPE: amino acid (C) STRANDEDNESS: (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 12: Asn Asp Cys Arg Asp He He Gin Arg Met His Leu Arg Gin Tyr 1 5 10 15 (2) INFORMATION FOR SEQUENCE IDENTIFICATION NUMBER: 13: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 24 (B) TYPE: amino acid (C) STRANDEDNESS: (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 13: Asp Thr Glu Asn He Arg Arg Val Phe Asn Asp Cys Arg Asp He He 1 5 10 15 Gin Arg Met His Leu Arg Gin Tyr 20 (2) INFORMATION FOR SEQUENCE IDENTIFICATION NUMBER: 14: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 15 (B) TYPE: amino acid (C) STRANDEDNESS: (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 14: Ala Ala Val Lys Asp Thr He Leu Gin Leu Asn Leu Lys Glu Tyr 1 5 10 15 (2) INFORMATION FOR SEQUENCE IDENTIFICATION NUMBER: 15: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 24 (B) TYPE: amino acid (C) STRANDEDNESS: (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 15: Asp Thr Glu Asn He Arg Phe Val Phe Ala Ala Val Lys Asp Thr He 1 5 10 15 Leu Gin Leu Asn Leu Lys Glu Tyr 20 (2) INFORMATION FOR SEQUENCE IDENTIFICATION NUMBER: 16: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 14 (B) TYPE: amino acid (C) STRANDEDNESS: (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 16: Asp Ala Val Thr Asp Val He He Lys Asn Asn Leu Lys Asp 1 5 10 (2) INFORMATION FOR SEQUENCE IDENTIFICATION NUMBER: 17: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 14 (B) TYPE: amino acid (C) STRANDEDNESS: (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 17: Asp Ala Val Thr Asp Val He He Lys Asn Asn Leu Lys Glu 1 5 10 (2) INFORMATION FOR SEQUENCE IDENTIFICATION NUMBER: 18: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 14 (B) TYPE: amino acid (C) STRANDEDNESS: (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 18: Glu Ala Ala Ser Tyr He Gin Ser Lys Phe Glu Lys Leu Asn 1 5 10 (2) INFORMATION FOR SEQUENCE IDENTIFICATION NUMBER: 19: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 10 (B) TYPE: amino acid (C) STRANDEDNESS: (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 19: Lys Asn Asn Leu Lys Asp Cys Gly Leu Phe 1 5 10 (2) INFORMATION FOR SEQUENCE IDENTIFICATION NUMBER: 20: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 15 (B) TYPE: amino acid (C) STRANDEDNESS: (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 20: Ala Ala Val Thr Asp Val He He Lys Asn Asn Leu Lys Asp Cys 1 5 10 15 (2) INFORMATION FOR SEQUENCE IDENTIFICATION NUMBER: 21: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 15 (B) TYPE: amino acid (C) STRANDEDNESS: (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 21: o Asp Ala Val Thr Ala Val He He Lys Asn Asn Leu Lys Asp Cys 1 5 10 15 (2) INFORMATION FOR SEQUENCE IDENTIFICATION NUMBER: 22: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 15 (B) TYPE: amino acid (C) STRANDEDNESS: (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 22: sp Ala Val Thr Asp Val He He Lys Ala Asn Leu Lys Asp Cys 1 5 10 15 (2) INFORMATION FOR SEQUENCE IDENTIFICATION NUMBER: 23: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 15 (B) TYPE: amino acid (C) STRANDEDNESS: (D) TOPOLOGY : linear ( xi ) SEQUENCE DESCRIPTION : SEQ ID NO : 23 : sp Ala Val Thr Asp Val He He Lys Asn Ala Leu Lys Asp Cys 1 5 10 15 ( 2 ) INFORMATION FOR SEQUENCE IDENTIFICATION NUMBER : 24 : ( i ) SEQUENCE CHARACTERISTICS : (A) LENGTH: 15 (B) TYPE: amino acid (C) STRANDEDNESS: (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 24: Asp Ala Val Thr Asp Val He He Lys Asn Asn Leu Lys Ala Cys 1 5 10 15 (2) INFORMATION FOR SEQUENCE IDENTIFICATION NUMBER: 25: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 9 (B) TYPE: amino acid (C) STRANDEDNESS: (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 25: Asp Ala Val Thr Asp Val He He Lys 1 5 (2) INFORMATION FOR SEQUENCE IDENTIFICATION NUMBER: 26: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 11 (B) TYPE: amino acid (C) STRANDEDNESS: (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 26: Asp Val He He Lys Asn Asn Leu Lys Asp Cys 1 5 10 (2) INFORMATION FOR SEQUENCE IDENTIFICATION NUMBER: 27: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 14 (B) TYPE: amino acid (C) STRANDEDNESS: (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 27: Arg Val Gly Leu Val Arg Gly Glu Lys Ala Arg Lys Gly Lys 1 5 10 (2) INFORMATION FOR SEQUENCE IDENTIFICATION NUMBER: 28: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 25 (B) TYPE: amino acid (C) STRANDEDNESS: (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 28: Leu Thr Ala Cys Leu Leu Thr Leu Leu Leu Tyr Arg Val Gly Leu Val 1 5 10 15 Arg Gly Glu Lys Ala Arg Lys Gly Lys 20 25 (2) INFORMATION FOR SEQUENCE IDENTIFICATION NUMBER: 29: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 15 (B) TYPE: amino acid (C) STRANDEDNESS: (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 29: Arg Arg Ser Ser Lys Phe Cys Leu Lys Glu His Lys Ala Leu Lys 1 5 10 15 (2) INFORMATION FOR SEQUENCE IDENTIFICATION NUMBER: 30: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 19 (B) TYPE: amino acid (C) STRANDEDNESS: (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 30: Arg Asn Gin Val Arg Lys Lys Arg Gin Met Ala Ala Arg Glu Arg Lys 1 5 10 15 Val Thr Arg (2) INFORMATION FOR SEQUENCE IDENTIFICATION NUMBER: 31: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 15 (B) TYPE: amino acid (C) STRANDEDNESS: (D) TOPOLOGY: linear ( xi ) SEQUENCE DESCRIPTION : SEQ ID NO : 31 : Asp Ala Val Thr Asp Val He He Lys Asn Asn Leu Lys Xaa Cys 1 5 10 15 (2) INFORMATION FOR SEQUENCE IDENTIFICATION NUMBER: 32: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 24 (B) TYPE: amino acid (C) STRANDEDNESS: (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 32: Asp Thr Lys Asn Val Gin Phe Val Phe Asp Ala Val Thr Asp Val He 1 5 10 15 He Lys Asn Asn Leu Lys Xaa Cys 20 (2) INFORMATION FOR SEQUENCE IDENTIFICATION NUMBER: 33: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 15 (B) TYPE: amino acid (C) STRANDEDNESS: (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 33: Asp Ala Val Thr Asp He He He Ala Xaa Asn Leu Arg Gly Cys 1 5 10 15 (2) INFORMATION FOR SEQUENCE IDENTIFICATION NUMBER: 34: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 22 (B) TYPE: amino acid (C) STRANDEDNESS: (D) TOPOLOGY : linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO : 34 : Asn Asn He Gin Xaa Val Phe Asp Ala Val Thr Asp He He He Ala 1 5 10 15 Xaa Asn Leu Arg Gly Cys 20 What is claimed is:

Claims: CLAIMS 1. A molecule comprising the anticouplone sequence of a G protein, wherein said molecule contains no more than 50 amino acid residues. 2. The molecule of claim 1, wherein said molecule contains no more than 30 amino acid residues. 3. The molecule of claim 1, wherein said G protein is a mammalian G protein. 4. The molecule of claim 2, wherein said molecule is a peptide the amino acid sequence of which is essentially identical to said anticouplone. 5. A molecule comprising the amino acid sequence DXXXXVIIKNNLXXC (SEQ ID NO: 1), wherein said molecule contains no more than 40 amino acid residues. 6. The molecule of claim 5, wherein said sequence is DAVTXVIIKNNLKXC (SEQ ID NO: 2) . 7. The molecule of claim 6, wherein said molecule comprises the amino acid sequence DAVTDVIIKNNLKDC (SEQ ID NO: 3) . 8. The molecule of claim 6, wherein said molecule comprises the amino acid sequence DTKNVQFVFDAVTDVIIKNNLKDC (SEQ ID NO: 4) . 9. The molecule of claim 5, wherein said molecule comprises the amino acid sequence DAVTDVIIKNNLKEC (SEQ ID NO: 5) . 10. The molecule of claim 9, wherein said molecule comprises the amino acid sequence DTKNVQFVFDAVTDVIIKNNLKEC (SEQ ID NO: 6) . 11. A molecule comprising the amino acid sequence DAVTXIIIAXNLRXC (SEQ ID NO: 7), wherein said molecule contains no more than 40 amino acid residues. 12. The molecule of claim 11, wherein said molecule comprises the amino acid sequence DAVTDIIIANNLRGC (SEQ ID NO: 8). 13. The molecule of claim 11, wherein said molecule comprises the amino acid sequence NNIQWFDAVTDIIIANNLRGC (SEQ ID NO: 9) . 14. The molecule of claim 11, wherein said molecule comprises the amino acid sequence DAVTDIIIAKNLRGC (SEQ ID NO: 10). 15. The molecule of claim 14, wherein said molecule comprises the amino acid sequence NNIQFVFDAVTDIIIAKNLRGC (SEQ ID NO: 11) . 16. A molecule comprising the amino acid sequence NDCRDIIQRMHLRQY (SEQ ID NO: 12) , wherein said molecule contains no more than 40 amino acid residues. 17. The molecule of claim 16, wherein said molecule comprises the amino acid sequence DTENIRRVFNDCRDIIQRMHLRQY (SEQ ID NO: 13). 18. A molecule comprising the amino acid sequence AAVKDTILQLNLKEY (SEQ ID NO: 14) , wherein said molecule contains no more than 40 amino acid residues. 19. The molecule of claim 18, wherein said molecule comprises the amino acid sequence DTENIRFVFAAVKDTILQLNLKEY (SEQ ID NO: 15) . 20. A method of inhibiting activation of a G protein by a G-coupled receptor on a cell, said method comprising contacting said cell with a molecule comprising the anticouplone sequence of said G protein, said molecule containing no more than 40 amino acid residues. 21. The method of claim 20, wherein said G protein is G ilf G i2 , or G i3 and said anticouplone sequence is DAVTDVIIKNNLKXC (SEQ ID NO: 31) or DTKNVQFVFDAVTDVIIKNNLKXC (SEQ ID NO: 32) . 22. The method of claim 21, wherein said G- coupled receptor is insulin-like growth factor II receptor (IGF-IIR) , muscarinic acetylcholine receptor (mAChR) , somatostatin receptor, D 2 -dopamine receptor, 2 - adrenergic receptor, adenosine receptor, thrombin receptor, or TGF3 receptor. 23. The method of claim 20, wherein said G protein is G ol or G o2 and said anticouplone sequence is DAVTDIIIAXNLRGC (SEQ ID NO: 33) or NNIQXVFDAVTDIIIAXNLRGC (SEQ ID NO: 34) . 24. The method of claim 23, wherein said G- coupled receptor is transforming growth factor-β receptor (TGF3R) , γ-butyric acid (GABA) receptor, somatostatin receptor, muscarinic acetylcholine receptor, adenosine receptor, thrombin receptor, or α 2 -adrenergic receptor. 25. The method of claim 20, wherein said G protein is G s and said anticouplone sequence is NDCRDIIQRMHLRQY (SEQ ID NO: 12) or DTENIRRVFNDCRDIIQRMHLRQY (SEQ ID NO: 13) . 26. The method of claim 25, wherein said G- coupled receptor is β 2 -adrenergic receptor, glucagon receptor, or D- j^ -dopamine receptor. 27. The method of claim 20, wherein said G protein is G g and said anticouplone sequence is AAVKDTILQLNLKEY (SEQ ID NO: 14) or DTENIRFVFAAVKDTILQLNLKEY (SEQ ID NO: 15). 28. The method of claim 27, wherein said G- coupled receptor is the T cell receptor, PTH/PTHrP receptor, calcitonin receptor, endothelin receptor, angiotensin receptor, platelet activating factor receptor, or thromboxane A 2 receptor.

Inventors: NISHIMOTO IKUO, NISHIMOTO, IKUO
Applicants: GEN HOSPITAL CORP, THE GENERAL HOSPITAL CORPORATION
Application year: 1994
Main classification: A61K37
IPC codes: A61K38, C07K14